Apparatus for cutting off sheet-metal containers

ABSTRACT

Apparatus for severing waste material from cylindrical sheetmetal containers, which apparatus includes an inside mandrel having a cutting edge formed along a predetermined parting line of a container inserted thereover. A counter tool in the form of a contact pressure piece is provided for pressing the container material radially inwardly to tear the same along the predetermined parting line by way of the tool edge of the mandrel. This contact pressure piece is spaced axially from the tool edge and between the tool edge and an abutment for the waste portion of the container material such that the counter tool acts only to exert pressure on the container material with the severing taking place at a position spaced therefrom. Since the tool edge of the mandrel and the contact pressure piece of the counter tool are spaced from one another, the counter tool experiences practically no wear and tear, while the arrangement advantageously provides a smooth, burr-free parting edge for the materials being severed.

United States Patent 1 1 Kannegiesser et al.

1 51 Apr. 8, 1975 1 APPARATUS FOR CUTTING OFF SHEET-METAL CONTAINERS[73] Assignee: L. Schuler Gmbll [22] Filed: Feb. 20, 1974 121] App].No.: 444,188

[30] Foreign Application Priority Data 3,756,103 9/1973 Cuacho et a182/85 Primary Examiner-Harrison L. Hinson Attorney, Agent, or FirmCraig& Antonelli [57] ABSTRACT Apparatus for severing waste material fromcylindrical sheet-metal containers, which apparatus includes an insidemandrel having a cutting edge formed along a predetermined parting line,of a container inserted thereover. A counter tool in the form of acontact pressure piece is provided for pressing the container materialradially inwardly to tear the same along the predetermined parting lineby way of the tool edge of the mandrel. This contact pressure piece isspaced axially from the tool edge and between the tool edge and anabutment for the waste portion of the container material such that thecounter tool acts only to exert pressure on the container material withthe severing taking place at a position spaced therefrom. Since the tooledge of the mandrel and the contact pressure piece of the counter toolare spaced from one another, the counter tool experiences practically nowear and tear, while the arrangement advantageously provides a smooth,burr-free parting edge for the materials being severed.

14 Claims, 2 Drawing Figures APPARATUS FOR CUTTING OFF SHEET-METALCONTAINERS BACKGROUND AND SUMMARY OF THE INVENTION This inventionrelates to an apparatus for the severing of sheet-metal containers,especially an apparatus for cutting of the scrap edge of sheet-metalcontainer blanks of the type wherein the blank is placed on a rotatingmandrel having a sharp tool edge extending along a predetermined partingline. The blank is then severed by means of a fixedly disposed orlikewise ro tating counter tool cooperating with the tool edge of themandrel. The customary cutting of sheet metal by a severing operationhas the disadvantage that the blades become rapidly blunt, due to theirclose mutual positioning, and a frequency change of the cutting tool isnecessary to obtain clean, burr-free cutting edges.

The invention contemplates apparatus which avoids the above-mentioneddisadvantages and which produces clean and smooth cutting edges.

More particularly, the present invention contemplates fashioning thecounter tool as a contact pressure piece which is arranged at a spacingfrom the tool edge of the mandrel between this tooledge and an abutmentfor the blank spaced axially, longitudinally of the mandrel. The tooledge and the contact piece are movable relatively to each other, thecontact piece extending preferably at an acute angle, to the workpiece(blank) and being rounded at its tip.

The advantages attained by the present invention reside particularly inthe essentially smaller wear and tear on the tool system, since the twotools are no longer close, almost touching contact with each other, asin prior arrangements, but rather are arranged at a mutual spacing.Therefore, essentially only the sharp tool edge on the mandrel is wornoff, while the contact tool experiences no wear and tear. Moreover,another important advantage attained is the feature of substantiallybetter, smooth, and. burr-free parting edges at the severed sheet-metalpieces, which is of special importance when cutting off the scrap edgefrom sheet-metal container blanks.

A preferred embodiment of apparatus constructed according to the presentinvention is illustrated in the drawings and will be described ingreater detail below. This preferred embodiment utilizes a relativelyfixed counter tool with the contact pressure piece formed therewith, anda mandrel for supporting the cylindrical container blanks which ismounted for rotation about the axis of the mandrel as well as forplanetary-like rotation of the complete mandrel assembly about an axisspaced from the mandrel axis. During operation of this preferredembodiment, the mandrel is rotated about its own axis as well as aboutthe axis spaced therefrom so as to bring the container into engagementwith the contact pressure piece of the counter tool.

Other preferred non-illustrated embodiments utilize a similarcross-sectional configuration of cutting edge at a support for thecontainer and counter tool contact pressure piece as in the illustratedembodiment. but with different means for relatively moving the materialbeing cut. the cutting edge. and the contact pressure piece with repectto one another. In one of these other preferred embodiments, the countertool and the cutting edge are formed on respective counter rotatingmembers which also have means for moving the respective axes of thesemembers toward one another to effect the severing operation. Thislast-mentioned preferred embodiment may utilize workpiece supports andcutter wheel constructions as in U.S. Pat. No. 2,702,597, however withthe cutting edges and counter tool constructed in accordance with FIG. 2of the present invention. A third preferred embodiment of the presentinvention utilizes a system such as disclosed in US. Pat. No. 3,425,251for supporting and moving the respective containers, cutting edges andcounter tools, however the cutting edges and counter tools are moditiedin accordance with FIG. 2 of the drawings of the present invention, asdescribed below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a part-sectional side viewwhich shows parts of an apparatus constructed in accordance with apreferred embodiment of the present invention for severing the scrapedge from a container blank; and

FIG. 2 is an enlarged sectional view which shows the cutting zoneillustrated in a circle in FIG. 1 on a larger scale.

DETAILED DESCRIPTIONS OF THE DRAWINGS The apparatus has a mandrel 2which rotates about an axle 1. Mandrel 2 and axle 1 are reciprocable inthe axial direction for purposes discussed further below. The right-handend of this mandrel 2 is conventionally fashioned as an annular cutter3. A ring 4, which is rotatably fixed with respect to axle l spaced tothe right of annular cutter 3. This ring 4 has a notch 6 at the endthereof facing the sharp cutting edge 5 of the annular cutter 3. As bestshown in FIG. 2, this ring 4 serves as an abutment for supporting andreceiving the scrap edge 7 of the container blank 8.

When the mandrel 2 is advanced to the left-hand p0 sition illustrated inFIG. 1, it enters a container blank 8 of sheet-metal which haspreviously been placed in front of the end face of the mandrel. Apressure member 10 resiliently contacts the bottom 9 of this blank 8 sothat the container blank 8 is held firmly against the mandrel 2. Mandrel2 is one of a plurality of similar mandrels supported on an axle 12which extends parallel to axle l of the individual mandrels. Mandrels 2are movable by way of bearing 11 around the axis of axle 12 duringoperation of the apparatus, as described in more detail below. As bestseen in FIG. 2, a notch 6 is provided at the ring 4, which notch 6extends over an arc of approximately 30 with respect to the axis ofaxle 1. This notch 6 faces the counter tool 13. It will be un derstoodthat a complete device contains several, for example three, unitsconsisting of parts indicated by reference numerals 1 to 6, 9, l0 and14. Each of these units are situated around axis 12 and rotatabletogether around this axle l2 and are rotatable together around this axle12 by means of bearing 11. During one rotation of the units around axle12, the following steps are performed consecutively:

blank 8 is positioned adjacent mandrel 2; mandrel 2 is then advanced(along with cutting tool edge 3, ring 4, etc.) in the direction of axle1 into blank 8; 1

scrap material portions 7 is severed by means of engagement with fixedtool 13;

3 mandrel 2 is retracted out of blank 8 along the direction of axis 1;blank 8 is then removed from mandrel 2 by means of stripper l4; andmandrel 2 is then moved into position adjacent another blank 8 forinitiating another sequence of operations. During all of theaboved-described steps, all of the units rotate around axle'l2 whilesimultaneously all mandrels 12, together with cutting tools 3 arerotated around their axes (planetary movement). Since means forproducing such a planetary movement in a container body forming machineare described and shown in U.S. Pat. No. 996,122, details thereof arenot included herein in order not to obscure "the present invention. Itis noted that the direction of rotation around axle 12 is to be oppositethe direction of rotation around the individual axles 1. It is furthernoted that rings 4 and strippers 14 do not take part in the planetarymovement but are rotatable around the axle 12 only along with the unitsassociated therewith. In the particular illustrated embodiment, the tool13 does not make any movement at all, with the individual blanks 8 beingmovable into engagement with the pressing edge of tool 13 by means ofthe planetary movement of the individual mandrels. It will also beunderstood that, with a complete device, several blanks will beprocessed in the device simultaneously, with different operations beingperformed at different positions about 7 rests during this forcing-offstep'with one end on the ring 4 acting as an-abutment, and is pressed,with the other end, into the notch or gap 6 of the ring 4. The followingadvantages are achieved by the arrangement of I the counter tool 13, 15as a non-cutting pressure tool.

Since the pressure tool acting as the counter tool need not operate infirm close contact with the edge of the annular cutter 3, said tool l5,13 can be arranged at a relatively large distance from the cutter edge 5in the order of 0.3 to 0.6 mm. In other words, the pressure tool 15, 13does not touch the annular cutter 3, so that the pressure tool 15, 13 issubjected to an essentially lower wear and tear than conventionalcutters used as counter tools. Due to the larger spacing of the pressuretool 15, 13 from the cutting edge 5 of annular cutter 3, the cutter 3 islikewise exposed to less wear and tear.

The wear on the pressure tool 15, 13 is even more reduced by providingthat the zone of the pressure tool pressing against the container blank8 adjoins a vertical (vertical or radial with respect to axle l andparallel to the end face of cutter 3) area 16 with a portion of smallradius 17 of, for example, 0.2 mm., in accordance with a further featureof the present invention. This radius 17 passes over, preferably but notnecessarily with a linear section l8,'into a further portion of smallradius 19, which radius 19 is in the range between the radius 17 andtwice the radius 17. This radius portion 19 is joined by an area 20tangentially therewith, which area 20 is inclined at an acute angle withrespect to the area tion 18 is maximally 1 mm and the axial dimension ofthe gap 6 is 3 to 5 mm with the radial dimension of the gap 6 being 2 to3 mm.

Due to the wide pressure zone of the pressure tool l5, 13, the scrapedge .7 is severed from'container blank 8 in a burr-free manner by thesharp edge 5 of the annular cutter 3, rather than being cut off by thepressure tool 15, 13.

The heretofore conventional cutters as a counter tool for the annularcutter 3are disadvantageous, in addition to producing a cutting edge atthe sheet metal which is not free of burrs and being subject to greattool wear, also because of another phenomenon: Since a radial play of,for example, 1-2 mm. is necessary between the container blank 8 and themandrel 2 so that the blank can be placed on the mandrel, the container'blank 8 will tumble to a minor degree on the mandrel during itsapproximately 1%. revolutions together with the mandrel while the scrapedge 7 is severed. As a consequence, in addition to the scrap edge 7,thin sheetmetal strips and splinters are severed from the containerblank 8 and furthermore the burred container edge is flanged inwardly.This is undesirable, because especially the container edge must beabsolutely burrfree, as well as exactly cylindrical at the end forpurposes of further processing of the container blank,

which is, for example, drawn,'stretch-for med, or exv Although this typeof severing contemplated by the I present invention comes closer to atearing off or breaking off of the scrap edge 7 from the container blank8 than a cutting operation, an edge .of such smoothness is produced atthe container blank 8 that no burr can be detected with the'naked eye orwith a small microscopic enlargement. Furthermore, the container edgepasses over into the cylindrical container wall without any seams orflanges, and a clean, ringshaped waste piece is obtained without anyadditional troublesome sheet-metal strips or splinters. Thus, it ispossible to create at the container blank 8 a container edge which alsosatisfies very high demands with respect to freedom of burrs at thecutting edge and a continuously smooth cylindrical shape .of thecontainer wall, in a simpler manner and with a more rugged counter tool,as well as with lesser wear and tear than heretoforev possible.

lf the tumbling motion-is partially or completely suppressed by holddowntool 21 which presses against the mandrel 2 during the severing step,this further improves the quality of the cutting edge at the'containerrim. Holddown tools of conventional configuration per se can be used inconjunction with the present i-nven-, tion as the tool 21. i g

Other preferred embodiments of the present invention utilize a pressuretool and cutting tool configuration as illustrated in FIG. 2 anddescribed above, however different mechanisms for moving the pressuretool and cutting tool with respepct to one another are provided. In oneother preferred embodiment, the basic work support and cuttingarrangement of US. Pat. No.

' 2,702,597 is modified by replacing anvil face 41 by a rotary toolformed with a cross-section similar to tool 13 of the presentapplication and with cutting edge 5 and gap 6 as shown in FIG. 2 of thepresent application In another preferred embodiment, the basicarrangement of US. Pat. No. 3,425,251 is utilized with knife sector 36of said patent being replaced by a rotary tool formed-like tool 13 ofpresent application and with an edge and gap such as 5 and 6 of FIG. '2of the present application included in place of cutter member 28 of thepatent.

It is further noted that the present invention can be applied in cuttingdevices of various types, such as shears or punching tools. The cuttingoperation can take place, as in the present illustrated embodiment,progressively along the parting line or simultaneously at once acrossthe entire parting line While we have shown and'described severalembodiments in accordance with the present invention, it is understoodthat the same is not limited thereto but is susceptible of numerouschanges and modifications as shown to hose skilled in the art and wetherefore do not wish to be limited to the details shown and describedherein but intend to cover all such changes and modifications as areencompassed by the scope of the appended claims.

We claim: v 1. Apparatus for severingsheet-material blanks comprising:

a blank holder for holding a blank, said blank holder having a sharptool edge extending along a predetermined parting line,

an abutment spaced from said sharp tool edge for abuttingly engaging aportion of said blank at the side of the material of said blank facingtoward said blank holder,

a countertool which is engageable with the side of said material facingaway from said blank holder for cooperating with said sharp tool edge tosever said blank along said parting line,

and moving means for moving said blank holder and countertool toward oneanother in the direction of the thickness of said sheet material toeffect a severing operation with severing of said sheet material alongsaid parting line,

.wherein the countertool is constructed as a noncutting contact pressurepiece which is disposed at a spacing from the tool edge between the tooledge and said abutment during said severing operations.

2. Apparatus according to claim 1, wherein said blank holder is ofcylindrical shape for engaging one of the inside and outside walls of ablank of cylindrical shape,and wherein said predetermined parting lineexsaid abutment is a cylindrical member of approximately.

the same diameterextending about the same axis as said mandrel, andwherein anannular gap is formed be- 'tween said tool edge and saidabutment for accommo dating relative movement of said counter tool andtool edge, as well as cut portions of blank, during said sever-' ingoperations. V

4. Apparatus according to claim 3, wherein said countertool is fixed inposition, and wherein said mov-v ing means includes means for movingsaid mandrel about an axis positioned outside of said mandrel andparallel to the axis of the mandrel, as well as means for rotating saidmandrel about the axis of the mandrel.

5. Apparatus according to claim 1, wherein said contact pressure pieceextends at an acute angle with respect to the sheet material of a blankbeing held by said blank holder and abutment.

6. Apparatus according to claim 3, wherein said contact pressure pieceextends at an acute angle with respect to the sheet material of a blankbeing held by said mandrel and abutment.

7. Apparatus according to claim 1, wherein said contact pressure pieceexhibits two rounded portions engageable directly with said sheetmaterial and spaced from one another in the direction from said tooledge toward said abutment, the rounded portion closest to the tool edgehaving a radius of curvature no greater than the radius of curvature ofthe other rounded portion.

8. Apparatus according to claim 3, wherein said contact pressure pieceexhibits two rounded portions engageable directly with said sheetmaterial and spaced from one another in the direction from said tooledge toward said abutment, the rounded portion closest to the tool edgehaving a radius of curvature no greater than the radius of curvature ofthe other rounded portions.

9. Apparatus according to claim 8, wherein said contact pressure pieceexhibits a straight portion c'on- Y said contact pressure piece which isinclined with respect to the axis of the mandrel.

11. Apparatus according to claim 10, wherein said annular gap exhibits ahalf V-shaped cross-section with the edge closest to the cutting edgeextending radially of the axisof the mandrel and the edge closest to theabutment inclined similarly as the inclined side of the contact-pressurepiece.

12. Apparatus according to claim 11, wherein said countertool is fixedin position, and wherein said moving means includes means for movingsaid mandrel about an axis positioned outside of said mandrel andparallel to the axis of the mandrel, as well as means for rotating saidmandrel about the axis of the mandrel.

countertool is rotatable approximately cylindrically shaped memberhaving an axis of rotation parallel to the axis of the mandrel, andwherein said moving means includes means for moving the axes of saidcountertool and mandrel toward one another, as well as means forrotating said mandrel and said countertool in respective oppositedirections.

1. Apparatus for severing sheet-material blanks comprising: a blankholder for holding a blank, said blank holder having a sharp tool edgeextending along a predetermined parting line, an abutment spaced fromsaid sharp tool edge for abuttingly engaging a portion of said blank atthe side of the material of said blank facing toward said blank holder,a countertool which is engageable with the side of said material facingaway from said blank holder for cooperating with said sharp tool edge tosever said blank along said parting line, and moving means for movingsaid blank holder and countertool toward one another in the direction ofthe thickness of said sheet material to effect a severing operation withsevering of said sheet material along said parting line, wherein thecountertool is constructed as a non-cutting contact pressure piece whichis disposed at a spacing from the tool edge between the tool edge andsaid abutment during said severing operations.
 2. Apparatus according toclaim 1, wherein said blank holder is of cylindrical shape for engagingone of the inside and outside walls of a blank of cylindrical shape, andwherein said predetermined parting line extends in a circle about thelongitudinal axis of said blank holder.
 3. Apparatus according to claim2, wherein said blank holder is constructed as a mandrel insertableinside of a cylindrically shaped container blank, wherein said abutmentis a cylindrical member of approximately the same diameter extendingabout the same axis as said mandrel, and wherein an annular gap isformed between said tool edge and said abutment for accommodatingrelative movement of said counter tool and tool edge, as well as cutportions of blank, during said severing operations.
 4. Apparatusaccording to claim 3, wherein said countertool is fixed in position, andwherein said moving means includes means for moving said mandrel aboutan axis positioned outside of said mandrel and parallel to the axis ofthe mandrel, as well as means for rotating said mandrel about the axisof the mandrel.
 5. Apparatus according to claim 1, wherein said contactpressure piece extends at an acute angle with respect to the sheetmaterial of a blank being held by said blank holder and abutment. 6.Apparatus according to claim 3, wherein said contact pressure pieceextends at an acute angle with respect to the sheet material of a blankbeing held by said mandrel and abutment.
 7. Apparatus according to claim1, wherein said contact pressure piece exhibits two rounded portionsengageable directly with said sheet material and spaced from one anotherin the direction from said tool edge toward said abutment, the roundedportion closest to the tool edge having a radius of curvature no greaterthan the radius of curvature of the other rounded portion.
 8. Apparatusaccording to claim 3, wherein said contact pressure piece exhibits tworounded portions engageable directly with said sheet material and spacedfrom one another in the direction from said tool edge toward saidabutment, the rounded portion closest to the tool edge having a radiusof curvature no greater than the radius of curvature of the otherrounded portions.
 9. Apparatus according to claim 8, wherein saidcontact pressure piece exhibits a straight portion connecting saidrounded portions which is parallel to the axis of said mandrel. 10.Apparatus according to claim 8, wherein the rounded portion closest tothe tool edge merges at the side thereof closest to the tool edge with aside of said contact pressure piece which is perpendicular to the axisof said mandrel, and wherein the other rounded portion closest to theabutment merges with a side of said contact pressure piece which isinclined with respect to the axis of the mandrel.
 11. Apparatusaccording to claim 10, wherein said annular gap exhibits a half V-shapedcross-section with the edge closest to the cutting edge extendingradially of the axis of the mandrel and the edge closest to the abutmentinclined similarly as the inclined side of the contact pressure piece.12. Apparatus according to claim 11, wherein said countertool is fixedin position, and wherein said moving means includes means for movingsaid mandrel about an axis positioned outside of said mandrel andparallel to the axis of the mandrel, as well as means for rotating saidmandrel about the axis of the mandrel.
 13. Apparatus according to claim3, wherein said countertool is a rotatable approximately cylindricallyshaped member having an axis of rotation parallel to the axis of themandrel, and wherein said moving means includes means for moving theaxes of said countertool and mandrel toward one another, as well asmeans for rotating said mandrel and said countertool in respectiveopposite directions.
 14. Apparatus according to claim 11, wherein saidcountertool is rotatable approximately cylindrically shaped memberhaving an axis of rotation parallel to the axis of the mandrel, andwherein said moving means includes means for moving the axes of saidcountertool and mandrel toward one another, as well as means forrotating said mandrel and said countertool in respective oppositedirections.